This invention is generally directed to telecommunications and is more specifically directed to features related to wireless subscribers and their availability.
Modern telecommunication systems provide a variety of features for subscribers. For example, wireline telephone subscribers may utilize incoming caller identification, voicemail, speed dialing, conferencing and call waiting to name a few of the available services and features. Some telephone companies also offer wireline subscribers a service in which a call will automatically be established between the calling party and a called party that had a busy line during an initial call origination when the called party's line becomes not busy. In general, wireline telephone subscribers have available many call services and features that are not available to wireless subscribers. This is due in part to the substantial history and development of wireline switching capabilities as compared to the relatively short history of wireless communication systems. It is also partially due to inherent differences between wireline and wireless systems, i.e. a wireline subscriber's line is always supported by the same telecommunication switch and is normally always connected as compared to a wireless subscriber that may be served by a variety of telecommunication switches at different times and may not be connected or available for significant periods of time.
Calls placed to a wireless subscriber have a substantially greater likelihood of not being completed as compared to calls placed to a wireline subscriber. As used herein “being completed” refers to the ability of the telecommunication system to establish a communication link to the called party's consumer premises equipment (wireless handset or wireline telephone) in response to a call origination request. A call origination to a wireless subscriber may not be completed due to a variety of factors. For example, the wireless subscriber's handset may be turned OFF or a radio frequency (RF) link between a supporting base station and the subscriber's handset may not be available. Even while in areas of generally good RF signal strength, a wireless subscriber may enter a localized area in which RF communications are poor or not available. Commonly known “RF dead zones” include tunnels, underground parking garages, areas within buildings surrounded by material that provides RF shielding or substantial attenuation, etc.
What happens when a party originates a call to a wireless subscriber that does not complete? The calling party will be typically given no indication of the reason for the lack of completion. Even for those wireless systems which provide an announcement indicating that the called wireless subscriber cannot be reached or located, the calling party is left to wonder whether the wireless subscriber is not active (e.g. cellular telephone turned OFF) or whether the wireless subscriber is merely experiencing temporary RF link unavailability, e.g. being in an RF dead zone. Other than an option of leaving traditional voicemail for the unavailable wireless subscriber, the calling party is left to periodically initiate new call originations to the desired wireless subscriber in an attempt to establish communications. Thus, there exists a need for improved services related to calls desired to be established with wireless subscribers.